The Effect of Fibrous Tows and Weave Pattern on Carbon Cloths as Electrodes in Redox Flow Batteries

The electrochemical and fluid dynamic performance of redox flow batteries is strongly influenced by the microstructure of the porous electrodes. Carbon cloths are a potential candidate whose hierarchical structure affects length scales associated with electrolyte flow; however, few studies have investigated the electrochemical behavior spanning from the fibrous tow to the bulk weave pattern. Here, we explore commercially activated weave patterns (plain, 8-harness satin, 2×2 basket) in an aqueous environment while quantifying reactive transport for individual tows and simulating fiber bundle electrochemical activity through multiphysics modeling. We then evaluate each woven electrode in a redox flow cell, measuring the pressure loss, polarization, and galvanostatic cycling behavior before comparing the mass-transfer relationships. We find the weave pattern strongly correlates with flow cell pressure drop, while the carbon fibers per tow influence electrochemistry and mass-transport scaling. Collectively, these results offer new insights into how advanced carbon cloths structures impact flow cell performance.